1. Field of the Invention
Aspects of the present invention relate to a device for driving a rear wheel of an electric vehicle, which can assemble a motor from the exterior side to the interior side of a vehicle, can simplify a structure of a trailing arm by providing a fastening part having a large outer diameter at a wheel side, can reduce the load of a motor cover by fastening the motor cover to the inside of the trailing arm and fastening an axle housing to the outside of the trailing arm, and can improve packaging performance by assembling a final gear and a tone wheel on a rear surface of a wheel while nut-fastening an output shaft on a front surface of the wheel, which is a dead space.
2. Description of the Related Art
As fossil fuels, such as petroleum or diesel, are running out, instead of fossil fuel-powered vehicles, development of electric vehicles using electric energy stored in batteries in driving a motor is being actively conducted.
Electric vehicles are classified into a true electric vehicle which drives a motor using only electric energy stored in a rechargeable battery, a solar cell vehicle which drives a motor using photovoltaic energy, a fuel cell vehicle which drives a motor using a hydrogen fuel cell, a hybrid vehicle which drives an engine using fossil fuel while driving a motor using electricity, and the like.
In general, a device for driving a rear wheel of an electric vehicle is configured such that a motor is integrated into a trailing arm, components of a motor, such as a rotor or a stator, are assembled from the inside to the outside of a vehicle body and are protected by a motor cover, and a spring is positioned on a side surface of a motor housing to avoid interference of the motor cover, as disclosed in “Drive device for driving a wheel for an electrically powered vehicle”, PCT publication No. WO 2012/123175 (Publication date: Sep. 20, 2012.
However, in the conventional rear wheel driving device of an electric vehicle, since the motor is assembled from a rear surface of the vehicle, it is quite difficult to install the components of the motor on the rear surface. As an alternative option, the components of the motor are limitedly installed on side surfaces of the motor.
In addition, in the conventional rear wheel driving device of an electric vehicle, a motor fastening part is positioned inside a wheel, and a speed reducer fastening part is positioned outside the wheel, making a trailing arm have a complex structure.